The present invention relates to an improved structure of an air pump for a fish bowl, and more particularly, to an improved practical structure of an air pump for a fish bowl which will greatly reduce the noise of operation.
Prior art structure of an air pump for a fish bowl, such as that being disclosed in Taiwan Pat. No. 59102, for example, generally has one-way discharge function by covering stoppers onto thin diaphragms at the discharge valve ports. However, since the peripheries of the stoppers are plane surfaces, both the stoppers and the diaphragms will detach from their original portions due to continuous operation, and the discharge function of the pump stops accordingly. It is mainly because the stoppers are too thin and the contact face of the stoppers' peripheries with intake/discharge ports is rather straight that they will inevitably slip away and finally detach from their position under continuous vibration in long term operation.
There are some other air pumps for fish bowls, having an upwardly projecting one-piece molded rod at the center of the discharge valve port onto which a rubber diaphragm with a central opening may be put to cover the valve port to effect one-way discharge function. Even with such a structure, the contact face of the diaphragms with the valve ports is still not large enough to keep them from detachment under constant push by the air. Once the diaphragms would even slightly slip away from their original positions, they would not be able to tightly engage with the discharge valve port, and the air would soon flow in reverse and finally lead to insufficient discharge of air. The users, consequently would have to frequently check and even repair the diaphragms to maintain the normal operation of the pump. This obviously causes the users a lot of unnecessary trouble.
It is an important object of the present invention to provide an improved structure of an air pump for a fish bowl, wherein two rubber-made diaphragms with a one-piece molded projecting rod are inserted into the engaging holes centered at the air circulating ports respectively so that the contact face of the diaphragms with the air circulating ports and the friction force so produced over there will be large enough to meet the expected requirement of fixing the diaphragms and preventing them from detachment.